The application is for partial support of the annual Gordon Research Conference on Cancer. The conference aims to address, in a single meeting, the molecular, cellular, and systemic mechanisms that contribute to variability in the development and progression of neoplasia. The meeting will be attended by 130 scientists representing universities, research institutes, industries and government agencies. The 1987 conference will consist of 9 plenary sessions, each including a Chairman and two or three scheduled speakers. Time will be allotted for extensive audience discussion. In addition, there will be 3 informal sessions: (1) a poster session, (2) a discussion session on model systems, and (3) a discussion session on new techniques in molecular biology. Discussion leaders and speakers are drawn from outstanding and innovative scientists. The sessions will focus on the Role and Mechanisms of Variability in Tissue and Population Biology and include presentations on Tumor Progression and Evolution, Genetic Mechanisms of Variability, High Frequency Variation, Oncogenes Roles in Variation, Multifactoral Regulation of Normal and Neoplastic Development, Tissue Regulation of Normal and Neoplastic Expression, Dietary Effects on Cancer, Neuroendocrine and Neuroimmune Regulation in Cancer, and Molecular Genetic Approaches to Cancer Epidemiology. The impact of this integrated, multidisciplinary conference should be in stimulating thought and new research on the bases for neoplastic development and progression.